» Clofibrate Capsules contain not less than 90.0 percent and not more than 110.0 percent of the labeled amount of C12H15ClO3.
Packaging and storage Preserve in well-closed, light-resistant containers.
USP Reference standards 11
Identification Capsules respond to Identification test A under Clofibrate.
Medium: sodium lauryl sulfate solution (5 in 100); 1000 mL.
Apparatus 2: 100 rpm.
Time: 180 minutes.
Determine the amount of C12H15ClO3 dissolved by employing the following method.
Mobile phase Prepare a degassed and filtered mixture of methanol and water (80:20).
Standard solution Transfer about 20 mg of USP Clofibrate RS, accurately weighed, to a 50-mL volumetric flask. Add 20 mL of methanol, mix to dissolve the clofibrate, dilute with water to volume, and mix. Dilute an aliquot quantitatively with methanol to obtain a final solution having a known concentration of about 80 µg per mL.
Test solution Dilute a 5.0-mL portion of the solution under test to 25.0 mL, using methanol. Allow to stand for 5 minutes, and filter.
Chromatographic system The liquid chromatograph is equipped with a 226-nm detector and a 4-mm × 30-cm column that contains packing L1. The flow rate is about 1 mL per minute. Chromatograph the Standard solution, and record the peak responses as directed for Procedure: the tailing factor is not more than 1.5; and the relative standard deviation for replicate injections is not more than 2.0%.
Procedure Separately inject equal portions (about 20 µL) of the Standard solution and the Test solution into the chromatograph, record the chromatograms, and measure the responses for the major peaks. Calculate the amount of C12H15ClO3 dissolved.
Tolerances Not less than 80% (Q) of the labeled amount of C12H15ClO3 is dissolved in 180 minutes.
Uniformity of dosage units 905: meet the requirements.
Assay Proceed with Capsules as directed in the Assay under Clofibrate, using the following as the Assay preparation: Weigh accurately not less than 20 Capsules in a tared weighing bottle. With a sharp blade, carefully open the Capsules, without loss of shell material, and transfer the contents to a 100-mL beaker. Remove any liquid from the emptied capsules by washing with several small portions of ether. Discard the washings, and allow the capsules to dry in a jet of dry air until the odor of ether no longer is perceptible. Weigh the empty capsules in the tared weighing bottle, and calculate the average net weight per capsule. Transfer an accurately weighed amount of capsule contents, equivalent to about 200 mg of clofibrate, to a 100-mL volumetric flask, add methanol to volume, and mix. Transfer 10.0 mL of this solution to the Ion-exchange column, and collect the eluate in a 100-mL volumetric flask. Rinse the column with 25 mL of methanol, collect the rinsings in the volumetric flask, dilute with methanol to volume, and mix. Transfer 5.0 mL of this solution to a 50-mL volumetric flask, dilute with methanol to volume, and mix. Calculate the quantity, in mg, of C12H15ClO3 in the portion of Capsules taken by the formula:
10C(AU / AS)in which C is the concentration, in µg per mL, of USP Clofibrate RS in the Standard preparation; and AU and AS are the absorbances of the Assay preparation and the Standard preparation, respectively.
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USP35NF30 Page 2720